1. Field of the Invention
This invention relates to a cell adapter or, more particularly, to a cell adapter attachable to an electric cell that is not of a predetermined standard dimension in order to give a standard size, that adapter being so designed that the body of the adapter can easily be formed as an integral unit and that the cell can easily be inserted into or removed from the body as well as can be held firmly in place when inserted therein.
2. Description of the Prior Art
Electric cells used as power sources for various kinds of electric appliances are usually standardized in size such as UM1 type, UM2 type, UM3 type, etc., and in this respect the cell receiving space in the electric appliance is usually made of such a dimension as to properly accept cells of a standard size as mentioned above.
On the other hand, nickel-cadmium cells have recently been developed and are finding their use in many fields, for such a cell has so small an internal resistance that it can provide big discharge current, say several amperes, in spite of its small volume and can be quickly charged in several or ten and several minutes and, furthermore, it can be charged even after it has discharged until the voltage across it becomes almost zero.
Cells of this type can have sufficient capacity even if they are rather small in size and, in view of this, they are made of selected shapes and sizes which are different from the standards for conventional cells such as UM1, UM2, UM3, etc., so as to develop their own uses although there are some that have conventional standard sizes. It is desired, however, that these cells suited for their own uses, as mentioned above, could also be mounted in a cell receiving space designed for the accommodation of cells of a conventional standard size.
Recently, nickle-cadmium type cells of a standard size such as UM1, UM2, or UM3 have come into the market. However, such nickle-cadmium cells are expensive, and provision of cells of various sizes would make it impossible to expect the reduction of cost by mass-production. To enjoy the reduction of cost by mass-production, attempts have been made to use UM3 cells as UM2 or UM1 cells. For this purpose it has been proposed to provide cell adapters to be attached to nickle-cadmium cells so as to enable them to be placed in a conventional cell receiving space.
It is also to be noted that these nickel-cadmium cells are not only used as power source but also they are sometimes charged on a charger having a cell receiving space whose shape and size correspond to those of the cells' own. It is therefore desirable for the cell adapter not only to be attached to the cell in order to give it a desired outer dimension but also to be readily detached from the cell. This requires the cell adapter to hold the inserted cell by an elastic action in the direction of its diameter. Provision of such elastic holding means would make it difficult to make the cell adapter such as by solid molding of a synthetic resinous material.